Machine tool



Aprifi 3, 1951 P. A. NEWMAN 2,547,832

MACHINE TOOL Filed Aug. 29, 1947 7 Sheets-Sheet 1 1 N V EN TOR.

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P. A. "NEWMAN April 3, 1951 MACHINE TOOL 7'! Sheets-Sheet 7 Filed Aug.29, 1947 MAN Patented Apr. 3, 1951 UNITED STATES PATENT ()FFICE MACHINETOOL Percy A. Newman, La Fayette, Ind, ,assignor .to Ross Gear and ToolCompany, La Fayette, Ind, a corporation of Indiana Application August29, 1947, Serial No. 1'7 71,249

12 Claims.

This invention relates toamachine-forforming which projects parallel tothe rock shaft axis and is received in a generally helical groove in-acam operatively connected to the steering Wheel. The theoreticalmechanical advantage'of such a steering gear depends upon the ratiobetween angular movement of the scam and angular movement of the rockshaft, and may either vary or be constant throughout the range of camrotation.

'It'has previously been proposed, as in my prior Patent No. 2,234,382,granted March 11, 1941, to form a cam for a Ross steering gear byemploying a cutter corresponding in shape and size to the boss of thesteering gear and moving such cutter over a circular arc, correspondingto the path of boss-travel, through the blank as the latter is rotated,the ratio between the rate of blank-rotation and of cutter movementbeing controlled to produce a cam of the desired pitch characteristics.

It is the object of the present invention to improve the machine of myaforesaid prior patent. More specifically, it is an object of thisinvention to produce a cam-cutting machine adapted for automaticoperation and capable of proceeding automatically through a cycleincluding the steps of moving the cutter axially of itself intoassociation with the blank, feeding the cutter through the blank as thelatter rotates, retracting the cutter from association with the blank,returning it to its initial position, and releasing the blank.

Another object of the invention is to provide an automatic machine inwhich release of the blank from between headstock and ztailstock centersprior tothe completion of the cutting operation will be positivelyprevented.

A further object of the invention is to provide an improved means fortaking up lost motion or back-lash between the blank and the cuttermounting, whereby to insure uniformity in the width of the cam grooveand an accurate control of its pitch at all points throughout itsextent.

Other "objects of theinvention include the provision of an'improvedmeans for driving the cutter and the provision of cutter-positioningmechanism adapted for power operation and automatic control.

In carrying out my invention in its preferred form, I "mount the cutterspindle eccentrically within a rotating drum and parallel to thedrumaxis. The cutter spindle projects beyond the 'drum at both endsthereof, one projecting end of the spindle being adapted to receive thecutter and the other projecting end bearing a pulley beltconnected to anindependently mounted cutterdriving motor. To rotate the drum, it isprovided with a gear or gear-sector meshing with a rack controlled inposition by a movable cam the contour of which determines the pitch ofthe cam groove at any pointin its length. The cammoving mechanism isdriven from a headstock spindle which is directly and positivelyconnected with the'cam blank, so that the rate of cam move- .mentwill'depend .upon the rate at which the headstock spindle rotates. Totake up lost motion between the headstock spindle and the drum whichsupports the cutter, such .drum is provided with a second gear orgear-sector meshing with a second rack operatively connected to thepiston of a hydraulic cylinder in which there is maintained a fluidpressure such that the two racks exert opposing drum-rotating efforts.,Poweroperated means, conveniently hydraulic, is employed to move thedrum axially of itself and thus to move the cutter into and out ofassociation with the blank. The headstock spindle, and through it thecam-moving mechanism, is driven from areversible motor; and such motor,together with valves controlling the hydraulic drum-moving means and thetailstock, are automatically controlled by mechanism including switchesactuated by moving parts. The preferred machine also includes atailstock clamp which is automatically actuated at the beginning of eachcamvcutting operation to lock the tailstock in advanced,blank-supporting position until after the cutting operation hasheencompleted and the cutter restored to its initial position.

The accompanying drawings illustrate a .pre- -terred form of machineembodying my invention: Fig. l is-a front elevation of the machine, withparts thereof broken away; Figs. 2 and 3 are elevations, each with partsbroken away, illustrating respectively the left and right sides of themachine; (Fig. 4 is a fragmental view .similar to Fig. :3 showing amodified arrangement of parts; Fig.6 is a plan view of the entiremachine; Fig. 6 is a plan view, in partial section, of the work tableand associated parts; Fig. 7 is a vertical axial section through themechanism of .Fig. 6; Fig. .8 is a horizontal section through the upperpart-ctthemachine; Fig. 9 is a fragmental view similar to Fig. '1 but onan enlarged scale; Fig. .10 .(Sheet 1) is a diagrammatic .frontelevation of an arrangement of controllingswitches;

which is parallel but eccentric to the axis of the drum. The lower endof the cutter spindle l9 projects downwardly beyond the drum and isthere equipped for the reception of a milling cutter 26. Because of theeccentric position of the spindle [9 in the drum l8, the cutter 26 willmove over an arcuate path when the drum [8 is rotated in the housing H.The eccentricity of the cutter-spindle [9 corresponds to the centerlinedistance between the driven rock shaft and the cam-engaging boss in thesteering gear above referred to, and the shape and size of the cutter h20 corresponds to the size and shape of such boss.

For the purpose of supporting a cam blank in co-operative relation withthe cutter 20, a work table 22 supported on the base is formed toprovide a head-stock 23 and a tail-stock 24 which respectively supportaligned spindles 25' and 26 between the opposed ends of which a camblock 21 is adapted to be supported. The common axis of the spindles 25and 26 is horizontali. e., it lies in a plane normal to the axis. of thedrum |8-and the work table 22 is so 10- cated that the distance betweenthe spindle axis and the axis of the drum l8 corresponds to the distancebetween the receptive axes of the cam and rock shaft in the steeringgear.

The particular cam-blank shown in the draw-- ing comprises (Fig. 9) acentral cylindrical body portion, in which the cam-groove is to be cut,and reduced-diameter end portions 30 through In addition, the cam-blankis provided at i s opposite ends with centers by which it may be locatedlaterally of itself to be concentric with the spindles 25 and 26. Asshown, the centers a conical shape to the outer ends of the journals I30; but it is to be understood that fema e centers Y may be used ifdesired. The cylindrical body portion of the cam is provided at one endwith a which the cam may be rotatably supported in 4 the housing of thefinished steering gear.

Y are male centers 3| and 32 formed by imparting notch or groove 33 tofacilitate positive rotation of the cam-blank during the cutting of thecam groove.

Within the tail-stock spindle 26, which does not itself rotate, Iprovide a rotating center 35 formed at its outer end to receive thecenter 3! of the cam-blank.

spindle 25 is provided with an axially slidable The rotatable head socl-.'

center 36 which, like the tail-stock center 35, is

. provided at its outer end with an axial opening The adapted to receivethe blank-center 32. headstock center 36 is urged forwardly by a spring31, movement of the center under the infiuence of the spring beinglimited by a bolt 38.

For the purpose of transmitting toroue from the headstock spindle 25 tothe cam blank 21, an adapter 46 is secured to the end of the spindle.Such adapter is formed to engage a shoulder 4| on the cam blank tolocate the latter axially of itself with reference to the axis of thedrum [8.

In addition, the adapter is provided with a key 42 received in the notch33. in the cam body.

The shoulder 4| may be the inner case of a ball bearing through themedium of which the cam will be supported in the finished steering gear.

For the purpose of rotating the headstock spindle 25 there is secured toit (Fig. '7) a worm gear 45 meshing with a worm 46 which is operativelyconnected through gears 41 and 48 with a countershaft 49. Thecountershaft 49 extends outwardly from the headstock 23 (Fig. 6) and isthere provided with a pulley 50 connected by a belt or belts 5| with apulley 52 on the shaft of'a driving motor 53. In the preferred machine,the motor 53 is a reversible hydraulic motor; but other types of motorsmay be used if desired.

As will be obvious from the contruction so far described, theconformation of the groove cut in the cam blank 21 will depend upon therelation between the respective speeds of rotation of the headstockspindle 25 and the drum l8. To control such relative speeds, the drum I8and the spindle 25 are operatively interconnected through the medium ofa rectilinearly slidable cam carried on a cam-slide 55 (Fig. 1) which ismoved longitudinally of itself at a rate dependent upon the speed ofrotation of the spindle 25 and which, through an appropriate camfollower and o her mechanism to be hereinafter described, controls thespeed of rotation of the drum l8. The mechanism for moving the camslide55 longitudinally of itself comprises a vertically movable rack 56 whichis operatively connected to the cam-slide 55 through the medium of abolt 5'! and turnbuckle 58 (see also Fig. 3). The rack 56 is supportedfor vertical sliding movement in a housing 60 which, for a purpose tobecome apparent hereafter, is in turn vertically movable in ways 6!supported from the base [5. For the purpose of moving the rack 56vertically, it meshes with a pinion 63 which is fixed on a shaft 64rotatably mounted in the housing 60.

Exteriorly of the housing 60, the shaft 64 carries a driving gear 65which is adapted for operative connection with a pinion 66 fixed to therear end of the headstock spindle 25. The gear 55 may, as indicated inFigs. 3 and '7, mesh directly with the gear 66 or, if it is desired toreverse the relation between the direction of rotation of the headstockspindle 25 and the direction of movement of the cam-slide 55, the gear66 may, as indicated in Fig. l, mesh with an idler 61 rotatablysupported from the housing 60, such idler in turn meshing wi h the gear66 on the headstock spindle. By changing the relative sizes of the gears65 and 66, the ratio between the speed of movement of the cam-slide 55and the speed of rotation of the spindle 25 can be varied.

It is to make possible the use of different-sized gears 65 and 66 thatthe housing 60 is made vertically adjustable in the ways 6|. Anyconvenient means may be employed for locating the housing 6|] in theproper vertical position, the means indicated in the drawing (Fig. 3)comprising a nut 10 which is secured in the housing 6|] and whichreceives a vertical lead screw H rotatably mounted in the base I5. Thelead screw H may be connected through gearing 12 with an adjusting shaft13 which projects through the wall of the base I5 and is there pro videdwith a hand wheel 14 (Figs. 1 and 6).

The cam-slide 55 previously referred to is supported for verticalsliding movement in suitable guides 16 (Figs. 1 and 8) mounted on theop- .80 mounted in bosses BI on the slide 55. To

cate the compensator plate definitely in any po- ":sition of adjustment,it :is provided with arou- .:atc slots 282 which receive clamp screws.83 ex- .tcnding :into the cam slide.

' :Upon the compensator plate 18 there are '10- cated in fixed positionsa pair of cam segments:v 85 and 86 havin opposed surfaces which definebetween them a cam groove 88 extend-ingobliqufi- --.:ly of the path oftravel of the cam slide 55. Such Y groove receives a cam-iollowingroller 98 rotate ably mounted on a slide 91 supported for hor1-" aontalsliding movement from the housing 11. The slide 91 is rigidly connected,as by means of a bolt 92, with a rack 93 which meshes with a gear orgear-sector 94 rigid with the drum I8. .As the headstock spindle 25rotates it causes the cam slide 55 to move vertically at a speed bearinga definite ratio to the speed of spindle rotation; and as the cam-slide:55 moves yertically, the cam follower 9!] in the oblique groove 88moves horizontally at a controlled irate totmoye the rack '93 and causethedrum 1.8 to swing about its axis. Obviously, the ratio between therate of movement of the cam-slide 55 and the rate .of angularjmovementof the drum 18 about its axis .will depend upon the obliquity of thegroove 88.

'1 interconnection of the link :H'EI with the spindle 19 and bracket 108 coincide respectively with the -axis of the spindle and the axis ofthe pulley Mil.

The link 410 may be made of adjustable length to control the tightnessof the belt 105..

ltis desirable in most instances to provide for vertical movement of thedrum l8 and of the cutter :and cutter-spindle supported therefrom, Toaccommodate for such vertical drum movement, the drum may be providedwith an upwardly extending spindle-housing H2 (Fig. l.) which surroundsand :isconcentric with the spindle I9 and whiohisrotatably and slidablyreceived in the adjacent :end of the link H6. The link I ll] has anintegral extension I I3 .(Fig. v5) provided with an opening H4; and .aboss H5 projecting upwardly from the top of the column t6 carries aretainer 6 which overlies the link-extension H3. With such anarrangement, the link I I0 is confined to movement in a singlehorizontal plane by-the top of the column and the retainer H5, and hencedoes not bind :on the spindle-housing I I2 as the drum 18 :movesvertically. The opening H4 is of course :made sufficiently larger thanthe boss I I 5 To remove alllost-imotioncr backlash and thus to insurethat arcuate movement of the cutter 29 about the .axis of the drum J8will proceedata definite rate determined by the obliquity of the Ygroove 88, I apply to the drum It a load which opposes the effortexerted by the cam 85-435 on the cam follower. To this end, the drum I8is pro vided with a second gear or gear-sector I00v which meshes with arack IllI operatively connected to a piston I02 (Fig. 5 in a hydrauliccylinder I103? With this arrangement, two methods of operation arepossible depending upon which end of the cylinder N13 is connected to asource of fluid pressure during the cutting operation. In other words,the hydraulic mechanism can -be operated either to effect or to opposefeed of the rotating cutter 20 through theblank 2i. In'the formerinstance, the actual cutting effort is obtained from the hydraulicmechanism, and the rate of feed is controlled by the rate of verticalmovement I of a predetermined minimum load on themec'hanism which op aively connects the headstock, SpindlefZE Widths drum I8. thusinsuringthat an to prevent interference with movement of the link in its planeas the drum -I 8 rotates.

.. As has been noted above, thedrum I8 is axially slidable .as well asrotatable in the housing ll.

This permits the cutter 28 to be positioned properly with reference tothe blank-axis during the cutting operation and also permits the cutterto 'be elevated above the blank to provide greater clearance duringremoval and insertion of blanks.

To accommodate for axial movement of the drum 1 8 the pulley I95 has .aface-width great enough to enable it to remain in cooperative .relationwith the belts IE5, and the gear sectors 94 and H30 have face widthsgreat enough to enable them to -remain in meshing engagement with therespectively associated'racks -93 and .10 I. During the cuttingoperation, the vertical disposition of the cutter 20 maybe controlled bya cam or cam-segment 120 which is secured to the lower end of the druml6 :and which rests on a roller {I21 mounted on an axis radial ofthedrum. The roller I24 is supported on the upper end of a member 122which is mounted for vertical sliding :moylement in a housing I23secured to the base I5. In its lower end, the member I22 is providedwith a screw-threaded axial opening receiving a lead screw 122connected, as through gearing "1:24, with an :adiusti-ng wheel or crankI 26.

As will be obvious, with the spindle I18 urged downwardly by meanshereinafter described to hold the cam 12!] in contact with the rollerIZI,

'iBI) the vertical elevation of the cutter 2.0 during the cuttingoperation will depend upon the contour of the cam J20. By adjusting thewheel 1 4-26, the roller 121 may be raised or lowered .as

lost-motion in such mechanism will be taken up throughout thecam-cutting operation.

For the purpose of rotating the cutter spindle I9 it projects beyond theupper end of the drum [8 and the housing H, where his provided with a"pulley I85 connected by a belt or :belts .tflfi "to a drivegpulley Iton the shaft of .a spindle-drivrotates during the cam-cutting operation,the motor I03 "ismounted {on a bracket 109 whichis swingably supportedon a vertical axis from the top of the column 16 and which isconnectedby a slink 1 MI with'the spindle i9. The-axes or pivotaldesired to establish-for the spindle .a base elevation departures fromwhich are controlled by the cam. Change of elevation of the cutter 20during the cutting operation will ordinarily be relatively slight, asits chief purpose is to accommodate the cam to compensate for wear.

To move the spindle l8 vertically to offset .en easement anddisengagement of the cam .820 with the roller 121., it is'provided withanannular :groove Hill which receives a block .l3I pivotally mounted .onone arm of :a bell crank I32. The other end of the bell crank isoperatively :con 'nected with a piston 1.33 which is slidable in acylinder 134. i'Referring to Fig. :1, it will be :ob-

vious that upon the application of fluid pressure to the left-hand endof the cylinder I34, the piston I33 will be moved to the right to swingthe bell crank I32 and elevate the spindle I8, thus freeing the cutterI9 from engagement with the blank and/or providing more room for removaland insertion of the blank. Conversely, the application of fluidpressure to the right-hand end of the cylinder I34 will move the pistonI33 to the left to lower the spindle I8 and force the cam I20 intoengagement with the roller I2I.

Like vertical movement of the drum I8, advance and retraction of thetailstock spindle 26 may be accomplished by hydraulic means. To thisend, the tailstock spindle 26 (Fig. 7) is operatively connected with apiston I36 slidable in a cylinder I31 to either end of which fluidpressure can be applied by appropriate valve means.

Automatic or semi-automatic control of the machine may be provided inresponse to the movement of various parts. Conveniently, such automaticor semi-automatic control is exercised through the means of limitswitches, three of which are shown in Fig. 1. The switches there showncomprise a switch I40, actuated by the mechanism which moves the drum I8vertically, and two switches HI and I42 which are controlled in responseto movements of the rack 93. Means for operating the switches MI and I42may comprise a switch actuator I43 operatively connected (Fig. 8) withthe rack 93 as by being attached to the outer end of an arm I44projecting forwardly from the rack 93. Mechanism for operating theswitch I40 may comprise a pivoted lever I45, the rear end of which isoperatively connected with the piston I33 and the front end of whichco-operates with the switch I40.

For fully automatic operation of the machine, I may employ a thirdswitch, indicated at I41 in Fig. 10, controlled by movement of the rack93. As will be apparent from Fig. 10, the switches MI and I42 arecontrolled respectively by bosses I48 and I49 on the actuator I43, whilethe switch I4! is controlled by a dog I50 movably mounted on theactuator I 43. It is assumed in Fig. that during the cutting of the camthe rack 93 will move from right to left, and the dog I50 on theactuator I43 is arranged to override the switch I41 without operating itduring such forward feeding movement of the rack 93 but to actuate theswitch I41 during the return stroke of the rack. The manner in which theswitches I4I, I42, and I41, as well as the switch I40, control thevarious operations in the machine will be brought out hereinafter.

If desired, the tailstock 24 may be provided with means for locking thetailstock spindle 26 in advanced position to insure against accidentalretraction of the tailstock spindle and dropping of the blank 21 duringthe cutting operation. One suitable form of spindle-clamping means isillustrated in Fig. 11, where I have shown the tailstock 24 as providedwith a clamping member I52 mounted for sliding movement generallytangentially of the tailstock spindle 26 and provided with aspindle-engaging surface I53. The clamping member I52 may projectlaterally from the tailstock 24 into association with a solenoid I54which, when energized, will operate to force the spindle-clampingsurface I53 against the spindle 2'6 and prevent itslongitudinalmovement.

As a source of fluid under pressure for use in advancing and retractingthe tailstock spindle 26, in raising and lowering the drum I8, inactuation of the rack IOI and in operating the motor 53, I may employ apump I56 adapted to be driven by an electric motor I51. Conveniently,the pump I56 is located in a sump I58 associated with the base I5 of themachine and is arranged to draw liquid from such sump and to dischargeit, under the control of valves to be described hereinafter, to thevarious hydraulically oper-,

ated devices.

In Fig. 12 I have illustrated diagrammatically one arrangement ofelectrical and hydraulic connections by which completely automaticcontrol of the cam-cutting machine may be effected. As there indicated,the pump I56 withdraws liquid from the sump I 58 through a pipe I60 anddischarges such liquid under pressure into a pipe I6I. The pipe I6I hasassociated with it a pressure-relief valve I62 discharging into the sumpI50. The pipe I61, containing liquid under pressure, is adapted to beconnected by appropriate valve mechanism with the various hydraulicallyoperated devices fluid from which flows through a return pipe I63 to thesump I58.

Hydraulic operation of the tailstock spindle 26 is controlled by a valveI66 having a movable valve member I61 which can be moved alteratively toconnect either end of the cylinder I31 to the fluid supply line I6I andsimultaneously to connect the other end of the cylinder to the returnline I63. In the particular arrangement illustrated in Fig. 12, thevalve member I61 is movable under the control of a hand lever I68 and asolenoid I69, the solenoid operating when energized to connect theright-hand end of the cylinder I31 to the fluid-supply line I6I.

A similar valve I1I having a movable valve member I12 is employed tocontrol the supply of fluid to the cylinder I34 and thus to control ver'tical movement of the drum I 8. Movement of the valve member I12 iscontrolled by two solenoids I13 and I14, the former operating whenenergized to position the valve member I12 to connect the left-hand endof the cylinder 34 to the fluid-supply line I6I and the latter operatingwhen energized to connect the right-hand end of the cylinder I 34 tosuch fluid-supply line.

A third valve I16, similar to the valves I66 and HI and embodying amovable valve member I11, controls the supply of fluid under pressure tothe reversible hydraulic motor 53. That motor has two ports, which areconnected respectively to two ports of the valve I11 by conduits I 18and I19, and is so constructed as to rotate in one direction when fluidunder pressure is supplied to it through the conduit I18 and in theopposite direction when it receives fluid under pressure from theconduit I19. The valve member I 11 is biased, as by opposed springs I80,toward a neutral po ition in which neither of the conduits I18 and I 19is connected to the fluid supply line I63 and is adapted to be moved inopposite directions from such neutral position by two solenoids IOI andI82. The arrangement is such that when the solenoid I8I is energized thevalve member I 11 is moved to connect the conduit I18 to the supply lineI63 and the conduit I19 to the return line I 63. Conversely, when thesolenoid I82 is energized, .the valve member I11 is moved in the otherdirection into a position in which the conduit I19 is connected to thesupply line I6I and the conduit I18 to the return line I63. When neithersolenoid is energized, the springs I hold the valve member I11 in itsneutral position. For the purpose 9; of explaining operation, it isassumed that energization of the solenoid I8I to connect the conduit I18with the supply line I6I will result in forward rotation of the motor53, or rotation in the direction employed in the cam-cutting. operation.To control the speed of the motor during the camcutting operation, theconduit. I18. may embody a flow-regulating valve I83, and to preventsuch valve from reducing speed of the motor 53 during its reverserotation, a bypass including a check valve I 84 is provided around suchvalve.

The lost-motion take-up mechanism embody-v ing the rack IOI, piston I02,and cylinder I93, which imposes on the drum I8 a load opposing itsrotation during the cam-cutting operation, may conveniently becontrolled jointly with the motor 53. For this purpose, and as indicatedin. Fig. 12, the left-hand end of, the cylinder I93 is connected to theconduit I18 and the right-hand end to the conduit I19.

- The spindle-driving motor I03, the pump-driving motor I51, and thevarious solenoids above mentioned are arranged to. be controlled byindividual relays. Desirably, the motors. and solenoids are adapted tobe operated by some readily available current, such as the common 119volt, 60-cycle alternating current, while the various control relays arelow-:voltage relays operating on current derived from a step-downtransformer- I99 over conductors I9I and I92. One of such conductors I9Iand I92hoii1nofbersrpwaETAOI conductors, shown as the conductor I9 5,desirably includes a normally closed, master stop switch I93 which canbe manually opened at any time to de-energize all the control relays andstop operation of the machine.

' The supply current to the spindle-driving motor I98 is controlled by arelay I95 having contacts a in circuit with the motor I98, and two pairsof holding contacts I) and c. The winding of the relay I95 is connectedacross the relaysupply conductors I9I and I92 through a normally open,manually closable switch I96 with which the holding contacts 0 of therelay are in parallel. Upon a momentary closing of the switch I96, therelay I95 is energized to close all its contacts. Closing of thecontacts a results in supply of current to the spindle-driving motorI08, while closing of the contacts 6' completes a holding circuitincluding the winding of the relay I95 and thus maintains such relayenergized until the master stop switch I93 is opened. Closing of thecontacts b is without efiect on the relay I95, but does perform afunction to be hereinafter set forth.

The pump-driving motor I5? is controlled by a. relay I98 having contactsa controlling the supply of current to the motor I51 and a pair ofholding contacts b. 'The relay-winding I99 is connected acrosstheconductors I9I" and I92 in series with both a normally open, manuallyclosable switch I99 and with the contacts b of relay I95, while thecontacts b of relay I98 are connected in parallel with the switch I99.As a result of the fact that the winding of relay I99 is connected tothe conductors I9I and I92 through the contacts b of the relay I95, therelay I93 can be energized to cause operation of the pump-driving motorI51 only when the relay I95 is closed to cause operation of thespindle-driving motor I98. The two switches MI and I42, which areoperated in movement of the rack 93., are both double-pole, double-throwswitches each having two sets of contacts a and b one oi which, is

auassa open when the other is closed. The switch I41... which is alsooperated in movement of the rack 93 as above set forth, is a normallyopen, single-.. pole switch adapted to be closed momentarily near theend of the cutter-return stroke of therack 93. The switch I46, operatedby the mech v anism which raises and lowers the drum I8 is a single-poleswitch normally open when the drum I8 is. raised but closed when suchdrum is lowered.

The solenoid I69 which operates when energized to move. the valve memberI61 to, retract the tailstock spindle 26 is controlled by a relay 29I.The winding of the relay 21H is connected across the conductors I9I. andI92 in series with the normally open switch M1.

The solenoid I54, which operates when energized to lock the tailstockspindle against longitudinal movement, is controlled bya relay 292,.

the winding of which is, connected across thev conductors I9I and I92through the contacts 12 of limit switch I42.

The solenoid I14, which positions the valve. member I12 to, causelowering of the drum I8, is controlled by a relay 263 whose winding isconnected to the conductors I9! and. I92 through a normally open.ycle-start switch 2B4. The solenoid I 73., whi h P i ions the valvemembe il2 to cause raising of the drum I8, is. controlled y the contactsa of a relay 205 which also ern. bodies a set of. holding conta ts b.The windingof relay 265 is. connected through the. contacts a of limitswitch I4I to the conductors I9I and I92.

The remaining relays 296 and 261 respectively control solenoids IBI andI82 which, in turn, control operation of the motor 53, and the baclslash take up mechanism IIlIIIJ3. Each of those relays comprises pairs ofcontacts a con.- trolling the. associated solenoid. and a p f auxiliarycontacts I).

The winding of the relay 295 is includedin a circuit extending from theconductor I9I, through the contacts b of limit switch I4I, the relaywinding, the switch I46, and the contacts a of limit switch I42 to theconductor I92. The contacts bof relay 296, when closed, provideconnection of the winding of that relay to the switch I46 and contacts aof switch I42. The winding of relay 20! is connected in a circuitextending from the conductor I9I through the contacts b of limit switchI42, the relay winding, and the contacts b of relay 295 to the conductorI92. The contacts. b of. relay 2!" are in parallel with the contacts bof relay 295.

Operation Figs. 1, 2, and 8 illustrate the drum It as 10wered, the racks93 and I9I as at the midpoints of their respective range of movement,and the cutter 2n and cutter-spindle'le as at the midpoint of their areof travel. It will be under stood, however, that at the begi ning of acame cutting operation, the cutter 253 will be at one end of its arc oftravel.

The parts of the machine illustrated in Fig. 12 are shown in theposition existing. at. the start of a cycle. As previously indicated, itis assumed that. the drum-rotating rack 99 will move to the left duringthe cam-cutting operation, and'such rack will therefore be, at theright-hand limit of its travel with the boss I 49 of the. switchactuator plate I43 in engagement with the switch I42 to hold thecontacts a thereof closed and the conab rifs's tacts b thereof open inopposition to an appropriate biasing means incorporated in such switch.The other switch-actuating boss I48 will be disposed out of engagementand to the right of the limit switch MI, and an appropriate biasingmeans associated with such switch will maintain the contacts (1 thereofopen and the contacts b closed. At the beginning of the cycle, the drumI8 will be in its upper position to elevate the cutter and facilitateinsertion of a cam blank 21, and the piston I33 in the cylinder I34 willbe near the right-hand end of such cylinder, being held there by fluidpressure applied to the lefthand end of the cylinder under the controlof the valve I1I which was set in the position to accomplish that end byenergization of the solenoid I13 during the preceding cycle. Thetailstock 26 will be retracted by fluid pressure applied to theright-hand end of the cylinder I31 under the control of the valve I66.Energization of the solenoid I69 during the preceding cycle has resultedin a setting of the valve I66 which provides for the application offluid pressure to the right-hand end of the cylinder I31. All the relays20I, 202, 203, 205, 206, and 201 will be open.

To begin a cycle, the operator places a blank 21 between the headstockand tailstock spindles and operates the lever I68 to move the valvemember I61 of the valve I66 to the left. When this occurs, fluidpressure is applied to the lefthand end of the cylinder I31 to advancethe tailstock 26 and clamp the blank between the centers 35 and 36.Assuming that the spindledriving motor I08 and the pump-driving motorI51 have been started by successive momentary closings of the switchesI96 and I99, the operator now closes the cycle-start switch 204 toenergize the relay 203 and thereby cause current to be supplied to thesolenoid I14. Upon energization of such solenoid, the valve member I12is drawn to the right to connect the right-hand end of the cylinder I34to the fluid supply line I6I and the left-hand end of such cylinder tothe return line I63. As a result, the piston I33 will be moved to theleft in the cylinder I34 to swing the bell crank I32 in acounter-clockwise direction, and thus, in the manner previously broughtout, to lower the drum I8 until the cam I20 engages the roller I2I whichdetermines the vertical position of the cutter 20. In this leftwardmovement of the piston I33, the lever I45 (Fig. 8) operates to close theswitch I40. As both the contacts I4Ib and I42a are already closed,closing of theswitch I40 energizes relay 206 to cause current to besupplied to the solenoid I8I. The concurrent closing of the auxiliarycontacts I) of relay 206 completes a holding circuit which is inparallel with the series-connected switch I40 and contacts I4 2a butwhich includes contacts b of limit switch I4I. Energization of thesolenoid I8I causes the valve member I11 to move to the left from itsneutral position, thus connecting the conduit I18 to the fluid supplyline I6I and the As the cam slide 55 moves vertically, the cam" followertraverses the oblique groove 88 thus, under the assumed conditions,causing leftward movement of the rack 93 and clockwise (Fi 8) rotationof the drum I8. During this movement of the drum, the cutter 20 swingsin a circular arc; and as the blank 21 is being simultaneously rotated,the cutter forms in the blank a generally helical groove 21 such as isshown in Fig. 9.

As the rack 93 moves to the left from the position it occupies at thestart of the cycle, the switch-actuator boss I49 moves out of engagementwith the limit switch I42 to open the contacts a and close thecontacts 1) thereof. Opening of the contacts a of switch I42 is withoutany immediate effect on the relay 206; as such relay remains energizedby reason of the engagement of its contacts b in the holding circuit.Accordingly, the solenoid I8I remains energized and the motor 53continues to operate in the forward direction. Closing of the contactsI) of switch I42 completes a circuit from the conductor I9I, throughsuch contacts and the winding of relay 202 to the conductor I92.Energization of the relay 202 causes current from the supply line to besupplied to the solenoid I54 which operates to engage the tailstockclamp I52 to prevent any accidental release of the tailstock spindle.

When swinging movement of the cutter 20 has progressed far enough tocomplete the cutting of the groove in the cam blank, the boss I48 on theactuator I43 engages the switch I4I to close the contacts a thereof andopen the contacts b thereof. As the contacts b are in series with thewinding of relay 206, such relay is immediately deenergized tode-energize the solenoid I8I of the motor-control valve I16. The closingof contacts a of switch I4I causes energization of the relay 205, andthe resultant closing of contacts a of such relay energizes the solenoidI13 causing it to operate the valve I1I so that fluid under pressurewill be supplied to the left-hand end of'the cylinder I34. The fluidsupplied to the cylinder I34 moves the piston I33 therein to the right,thus causing the drum I8 to be elevated. Upon this upward movement ofthe drum I8, the switch I40 is restored to its normally open position;but no action occurs as the result of such switchopening as the circuitthrough the switch was previously broken by the opening of contacts I42aat the beginning of the cycle.

Simultaneously with the closing of the contacts a of relay 205 to causeelevation of the drum I8, the contacts b of such relay close to completea circuit from the conductor I9I through the closed contacts I 42b, thewinding of relay 201, and the contacts 20% to the conductor I92. Thiscauses energization of the relay 201, whose contacts a close to energizethe solenoid I82, which operates the valve I16 to reverse the flow offluid through the motor 53. The concurrent closing of the relay contacts201b completes a holding circuit which includes the winding of relay 201and the contacts b of limit switch I42.

The reversed rotation of the motor 53 moves the cam slide 55 to causethe rack 93 to move to the right, thus rotating the drum I8 to restorethe cutter to its initial position. As the rack 93 begins its rightwardmovement, the switchactuator boss I48 moves out of engagement with thelimit switch I4I to open the contacts a and close the contacts bthereof. The change in the condition of neither of these contacts hasany immediate effect on the movement of machine asse elements. Althoughopening of'the contacts MId I does de-energize the relay 2%,, interruptthe supply of. current to the solenoid I13, and open the contacts 20%,the valve member I12 remains in the position to which. it was moved whenthe solenoid [1.3 was initially energized and the re lay 20'! remainsenergized because its winding is included in the holding circuit:through contacts 20Ib and l mb. The closing of contacts I4I'b is withouteffect, as the circuit including the contacts and winding of relay 206was already open. In consequence, the solenoid I82 remains energized andthe motor 53' continues to operate in the reverse direction to move therack 93 to the 26 in the direction of retraction; but as the clamp I152is still engaged, the tailstock remains advanced.

Upon completion of the return movement of the rack 93, the projection Iail-on the switchactuator I43 re-engages the limit switch Hi2 to closethe contacts a and open the contacts 2') thereof. Closing of thecontacts a is without immediate effect as the circuit containing themhas already been opened; but opening of the contacts I42 opens thecircuits through both the relays 202 and 201, thus causingde-energization of the clamp-actuating solenoid I54 and of thevalvecontrolling solenoid ISZ. When the clamp-actuating solenoid 54 isde-energized, the clamp I52 is released; and fluid pressure in theright-hand end of the cylinder I31 retracts the tailstock 26.De-energization of the valve-controlling solenoid I82 frees the valvemember IT! for movement under the influence of the springs I83, whichoperate to restore such valve member to its neutral position in whichsupply of fluid to the motor 53 is shut oil, thus bringing. theheadstock. spindle and the cam slide 55 to rest.

When the machine operates in the manner above described, the mechanismincluding the rack IOI, sector I00, piston H12, and cylinder I03 actsmerely to take up lost motion or back-lash by insuring that the cam85-86 and the re mainder of the cutter-feeding mechanism. will, duringthe cutting, operation, never be subjected to a load less than apredetermined minimum. In this connection, it is to be noted that theheadstock spindle 25 forms an element of the powertransmitting traininterconnecting the motor 53 and the drum I8 and that, in consequefifi,all lost motion between the spindle 25 and the drum is taken up, andmaintained taken up throughout the cutting operation, by fluidpressure-in the cylinder I03.

It has been noted above that the mechanism I-I03 can be usedalternatively in two ways, either to take up lost motion while cutterfeeding effort is applied to the drum I8 through the. rack 9I and cam85-86 orto exert the cutterfeeding effort itself and to rotate the drum!8 at a rate controlled by the cam. The arrangeinent employed to provideoperation inthe first manner has already been described. To provide foroperation in the second manner it is necessary only to reverse theconnections between the cylinder I03 and the conduits I18 and I19 and toinsure the existence of sufficient-pressure in the cylinder I03 to forcethe cutter through the. blank during the cutting operation. In the firstcase, with the cam-groove 88 having the obliquity indicated in Fig. land with the racks ill and IUI moving to the left during the cuttingoperation, the reaction of the blank on the cutter and the pressure inthe left-hand end of the cylinder I03 both serve to hold thecam-follower 90 in contact with the cam-segment 86; and the latter, asit rises, rotates the drum I8, forces the cutter through the work, andcauses fluid under pressure to be expelled from the cylinder I 03. Inthe second case, under the same assumed conditions, fluid-pressure inthe right-hand end of cylinder I03 rotate the drum in the clockwisedirection,

urges the rack 9| to the left, and holds the cam fol-lower 90 in contactwith the cam-segment 85;

' and the latter,.as it rises, merely controls the rate at which thedrum rotates under the efiort applied to it by the rack IOI. In bothcases all lost motion between the drum and headstock spindle is takenup.

Fig. 12 is intended to represent one arrangement of connection andcontrol apparatus through which automatic operation of the machine maybe accomplished. O-ther arrangements are possible; and in most instancesit will be desirable to include in the apparatus switch mechanisms bywhich control of movements of individual parts may be exercised in ordertoiacllitate setting up the machine.

' The effective pitch of the cam cut by the machine will depend upon theshape of the camgroove 88', the setting of the compensator plate I8, andthe ratio of the gearing interconnecting theheadstock spindle with thecam-slide 55. If the cam-groove 38 is straight, the effective pitch ofthe cam will be uniform throughout the extent of the cam; but byemploying cam-segments and 86 which will provide a groove havingdifferently inclined portions, a cam of non-uniform pitch can beproduced. A steering gear embodying such a cam is disclosed in my priorPatent No. 2,071,235. Fine adjustments to efiect small changes incam-pitch may be secured by changing the angular position of thecompensator plate I 8 on the cam slide, while coarser adjustments toeffect larger changes in pitch may be secured by altering the ratio ofthe gear train interconnecting the headstock spindle and camslide. Thesame set of cam segments 85 and 86 can be used alternatively to outeither left-hand or right-hand cams by interposing the idler 61 in, orremoving it from, such gear train.

' While I have described my machine above as adapted to cut a cam-groovein a blank, it will be obvious that it is equally adapted to grinding acam previously out. 'To convert the machine to a grinder it is necessaryonly to substitute a properly shaped. abrasive wheel for the cutter 20and to employ a spindle-driving means which will provide an adequatewheel-speed.

I claim as my invention:

1 In a machine for forming generally helical cams, means including aheadstock spindle for supporting and rotating a cam blank, a rotatabletool spindle, a tool-spindle support rotatable about an axis parallelbut eccentric to the toolspindle axis, means for driving said toolspindle, means for moving said tool-spindle support axially of itself toadvance a tool in the tool spindle into and retract it from operativeassociation with a blank in said blank-supporting means, mechanism forrotating said tool-spindle supauaess l port and headstock spindle intimed relation, and control means responsive to advance of saidtoolspindle support for automatically initiating operation of saidspindle-rotating mechanism.

2. In a machine for forming generally helical cams, means including aheadstock spindle for supporting and rotating a cam blank, a rotatabletool spindle, a tool-spindle support rotatable about an axis parallelbut eccentric to the toolspindle axis, means for driving said toolspindle, means for moving said tool-spindle support axially of itself toadvance a tool in the tool spindle into and retract it from operativeassociation with a blank in said blank-supporting means, mechanism forrotating said tool-spindle support and headstock spindle in timedrelation, and control means controlled by rotation of said toolspindlesupport for automatically causing said support-moving means to retractthe tool from association with the blank.

3. In a machine for forming generally helical cams, means including aheadstock spindle for supporting and rotating a cam blank, a rotatabletool spindle, a tool-spindle support rotatable about an axis parallelbut eccentric to the toolspindle axis, means for driving said toolspindle, means for moving said tool-spindle support axially of itself toadvance a tool in the tool spindle into and retract it from operativeassociation with a blank in said blank-supporting means, mechanism forrotating said tool-spindle support and headstock spindle in timedrelation, and control means comprising devices responsive to rotationand axial movement of said tool-spindle support for causing the machineto proceed automatically through a cycle including the steps ofadvancing the tool-spindle support, rotating such support from apredetermined initial position, retracting the support, and rotating itreversely to its initial position.

4. In a machine for forming generally helical cams, means including aheadstock spindle and a tailstock spindle for supporting and rotating acam blank, said tailstock spindle being axially movable into and from anadvanced, blank-supporting position, means for locking said tailstockspindle in said advanced position, a rotatable tool-spindle, atool-spindle support rotatable about an axis parallel but eccentric tothe toolspindle axis, means for driving said tool spindle, means formoving said tool-spindle support axially of itself to advance a tool inthe tool spindle into and retract it from operative association with ablank in said blank-supporting means, mechanism for rotating saidtool-spindle support and headstock spindle in timed relation, andcontrol means automatically controlled in response to movement ofsaidtool-spindle support for actuating said locking means andmaintaining it actuated throughout cam-forming rotation of saidtool-spindle support.

5. In a machine for forming generally helical cams, means including aheadstock spindle and a tailstock spindle for supporting and rotating acam blank, said tailstock spindle being axially movable into and from anadvanced, blank-supporting position, means for locking said tailstockspindle in said advanced position, a rotatable tool spindle, atool-spindle support rotatable about an axis parallel but eccentric tothe tool-spindle axis, means for driving said tool spindle, means formoving said tool-spindle support axially of itself to advance a tool inthe tool spindle into and retract it from operative association with ablank in said blank-supporting means, mecha- 16 nism for rotating saidtool-spindle support and headstock spindle in timed relation, andcontrol means comprising devices responsive to rotation and axialmovement of said tool-spindle support for causing the machine to proceedautomatically through a cycle including the steps of advancing thetool-spindle support, actuating said locking means, rotating saidsupport from a predetermined initial position, retracting the support,rotating it reversely to its initial position, and releasing saidlocking means.

6. A machine as set forth in claim 3 with the addition that the meansfor rotating the headstock spindle and tool-spindle support comprises areversible motor, said control means operating to reverse said motorfollowing the completion of rotation of the tool-spindle support fromits initial position.

7. In a machine for forming cams and the like, headstock and tailstockspindles, said tailstock spindle being advanceable into and retractablefrom an operative position in which it cooperates with the headstockspindle to support a blank, means operable to bias said tailstockspindle for retraction, locking means for holding said tailstock spindleadvanced, a tool spindle, a movable support therefor, means for movingsaid support from an initial position to cause a tool in the toolspindle to act on the blank and for subsequently restoring the supportto its initial position, a device responsive to movement of said supportfor releasing said locking means as said support approaches its initialposition, and means also responsive to movement of said support andoperable prior to operation of said last-named device for actuating saidbiasing means.

8. In a machine for forming generally helical cams, means including aheadstock spindle for supporting and rotating a cam blank, a rotatabletool spindle, a tool-spindle support rotatable about an axis parallelbut eccentric to the toolspindle axis, means for driving said toolspindle, means for moving said tool-spindle support axially of itself toadvance a tool in the tool spindle into and retract it from operativeassociation with a blank in said blank-supporting means, adjustablemeans for varying the ad-: vanced position of said support, andmechanism for rotating said support and headstock spindle in timedrelation.

9. In a machine for forming generally helical cams, means including aheadstock spindle for supporting and rotating a cam blank, a rotatabletool spindle, a tool-spindle support rotatable about an axis parallelbut eccentric to the toolspindle axis, means for driving said toolspindle, power-operated means for moving said tool-' spindle supportaxially of itself to advance a tool in the tool spindle into and retractit from Operative association with a blank in said blank-supportingmeans, adjustable means for varying the advanced position of saidsupport, and mechanism for rotating said support and headstock spindlein timed relation.

10. In a machine for forming generally helical cams, means including aheadstock spindle for supporting and rotating a cam blank, a rotatabletool spindle, a tool-spindle support rotatable about an axis parallelbut eccentric to the toolspindle axis, means for driving said toolspindle, hydraulic means for moving said tool-spindle support axially ofitself to advance a tool in the tool spindle into and retract it fromoperative association with a blank in said blankr-support- 17 in: means,adjustable means for limiting advance of said support by said hydraulicmeans, and mechanism for rotating said support and headstock spindle intimed relation.

11. A machine as set forth in claim 8 with the addition that saidadjustable means comprises a cam rigid with said support, a cam-engagingroller, a roller-support, and means for adjusting said roller-supportaxially of said tool-spindle support.

12. In a machine for forming generally heliical cams, means including aheadstock spindle for rotatably supporting a cam blank, a rotatable andaxially movable spindle-support, a tool spindle eccentrically mounted insaid spindlesupport, reversible hydraulic means for moving saidspindle-support axially of itself to advance a tool in said tool spindleinto and retract it from 18 operative association with a blank in saidblanksupporting means, and. reversible hydraulic means for rotating saidheadstock spindle and tool-spindle support in timed relation.

PERCY A. NEWMAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,275,985 Bock Aug. 13, 19181,687,260 Ross Oct. 9, 1928 1,871,174 Gruenewald Aug. 9, 1932 1,960,460Schurr May 29, 1934 2,448,426 Galloway Aug. 31, 1948

